Corynebacterium diphtheriae Outbreak in Migrant Populations in Europe

A surge of toxigenic Corynebacterium diphtheriae infections emerged in European migrant reception centers in mid-2022, marking the largest outbreak in western Europe in 70 years. This multicenter study analyzed 363 isolates from 362 patients across 10 countries, with cutaneous (77.5%) and respiratory (15.3%) manifestations predominating. Genomic sequencing revealed four major genetic clusters (ST377, ST384, ST574), indicating multiclonal origins linked to migration routes through the western Balkans. Antimicrobial resistance genes (ermX, pbp2m, *blaOXA-2*) were detected, threatening first-line treatments. Epidemiologic data highlighted vulnerabilities among male migrants (98.1%) from Afghanistan and Syria, with overcrowded conditions exacerbating transmission. Despite public health interventions, sustained transmission persisted into 2023, including secondary cases in non-migrant populations. The study underscores the urgent need for enhanced vaccination, antimicrobial stewardship, and genomic surveillance to mitigate outbreaks in displaced populations and prevent spillover into vulnerable groups.

A surge of toxigenic Corynebacterium diphtheriae infections emerged in European migrant reception centers in mid-2022, marking the largest outbreak in western Europe in 70 years. This multicenter study analyzed 363 isolates from 362 patients across 10 countries, with cutaneous (77.5%) and respiratory (15.3%) manifestations predominating. Genomic sequencing revealed four major genetic clusters (ST377, ST384, ST574), indicating multiclonal origins linked to migration routes through the western Balkans. Antimicrobial resistance genes (ermX, pbp2m, *blaOXA-2*) were detected, threatening first-line treatments. Epidemiologic data highlighted vulnerabilities among male migrants (98.1%) from Afghanistan and Syria, with overcrowded conditions exacerbating transmission. Despite public health interventions, sustained transmission persisted into 2023, including secondary cases in non-migrant populations. The study underscores the urgent need for enhanced vaccination, antimicrobial stewardship, and genomic surveillance to mitigate outbreaks in displaced populations and prevent spillover into vulnerable groups.